We asked four of our regular economics writers to examine a key theme they expect to flare up in 2018 and why.

Prime Minister Justin Trudeau and his wife, Sophie Gregoire, meet with Chinese President Xi Jinping and his wife, Peng Liyuan, before dinner at the G20 Leaders Summit in Hangzhou, China in September 2016. Trudeau is in China to discuss a trade deal.
THE CANADIAN PRESS/Adrian WyldDecember 2, 2017

Prime Minister Justin Trudeau is in China to discuss a trade deal. It's laughable for Canada to believe it can negotiate a "progressive" trade agenda with the Chinese.

U.S. President Donald Trump, right, talks with British Prime Minister Theresa May in Italy in May at a G7 summit. Trump has crowed about a “very quick” U.S.-U.K. trade deal.
(AP Photo/Luca Bruno)November 22, 2017